Here's a closeup of the iron work on that bowl above (photo by friend who owns the bowl)

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A reasonable shot of that same celadon on stoneware (sold item). Note the extremem difference in color due to iron in the clay, as well as the wispy blue in the bottom of this bowl. I only get that in pieces with a fair amount of ash- lots of discussion on the chemistry reason for it, but suffice to say- I get a little smile when I see these little galaxies in a pot.

The secret to this kind of "crackle" (or craze) is working with the Coefficient of Thermal Expansion of the glaze....... when I want this to happen to this extent, I shoot for about 8.8 x 10-6 in in/deg. C .

That means the glaze shrinks a lot once the glaze has "set (frozen) and the kiln is still cooling. WAY more than the underlying clay body does. Glass is strong in compression but weak in tension. result.... it relieves the stress between the clay and the glaze by cracking.

John- very nice! I was "loaned" some frit used in an ice crackle glaze recipe recently, but it was too late for the last firing. I think part of the trick is getting that expansion in a normally silica-rich glaze. They tend to be very high feldspar, correct?

I was first attracted to that deep scaled effect when I saw one of Gene's guinomi sporting it.

They have some Xu De Jia cups and pots very similar to what's being sold on Red Blossom, but a bit cheaper.

You can also get very reasonable celadon pieces on Etsy: http://www.etsy.com/search/handmade/ceramics_and_pottery?q=celadon&view_type=gallery&ship_to=US

I bought several Xu De Jia celadon pieces from Red Blossom; they weren't cheap but I don't regret it because I love them. I also but a mug from Etsy, and it gives some beverages a slightly funny flavor, LOL, hopefully I won't keel over from drinking out of it.

I couldn't get a good shot of the interior, unfortunately, but the interior curves are very lovely, especially when filled with tea. And there's some lovely iron-spotting to add to the depth of the glaze as well.

debunix wrote:That's gorgeous! Swirly and delicate and color fading and merging into the curves, and I bet it feels excellent in your hands.

It definitely does--the dip in the 'waist' of the cup is really nice to curl your fingers around. I've found that really seems to be a theme with Nathan's work--while not all of it might not necessarily appeal to my particular visual aesthetic, all of the cups I've purchased so far are very light and comfortable to hold. And of course, I really enjoy watching how the celadon changes over time.

Thought I would post some variants- these are cross posted elsewhere. The first is what happens when celadon is blasted by wood fire to pretty extreme temperatures. Note the blue in the drip at the foot- similar to that seen in the chawan I posted previously.

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The next shows what happens when rust is brushed on- burning through and mixing in. You see also see this in natural clays or glazes with less processed materials that have iron inclusions that spot. Lots of crazing with this glaze on porcelain, less on stoneware. The ash from the fire makes the glaze expand/contract more with heat, increasing the crazing. This was fired 2 months ago: no aging is required for crazing!

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Last is the foot of a porcelain yunomi showing some deepening of color where the glaze dripped.